You chair the Governor’s task force on rollout of the Covid-19 vaccine. We also examined a novel dosing strategy in which a delayed second dose regimen is used for people younger than 65 years old, but not before fully vaccinating older people. For further information on the agent based modeling and the exact vaccine prioritization under each strategy considered, please see the supplementary materials (appendix 1). Including the first 12 days underestimates the true vaccine efficacy because sufficient time to develop immunity had not occurred. This suggests that the delayed second dose strategy is optimal for vaccination rates at or below 0.3% population per day if the vaccine efficacy from one dose is 80% or greater. Interventions Simulation of standard covid-19 vaccination versus delayed second dose vaccination prioritizing the first dose. To date, our study is the first to analyze the impact of delaying a second dose for the BNT162b2 and mRNA-1273 vaccines under conditions we believe are necessary for decision makers considering second dose delay strategies. Delaying second Covid vaccine cuts death toll by up to a FIFTH compared to standard three-week spacing gap, study finds. Delaying the second dose but prioritizing it for people aged ≥65 can result in lower mortality rates compared with the standard two dose strategy, even at vaccination rates up to 1% of the population per day. These results suggest that higher first dose efficacy estimates favor delaying the second dose and that for a first dose efficacy of 70% or below, no meaningful difference is apparent between the standard and delayed second dose strategy. While the UK’s approach has been supported by many scientists, it lacks the rigor of controlled testing the UK is so well-versed in. Or should those who have gotten the first dose receive the second dose according to the standard schedule, 3 to 4 weeks after the first dose, as recommended by the Food and Drug Administration (FDA)? In both trials, the cases in the placebo and active vaccine groups began to diverge about 10 days after the first dose, with growing vaccine efficacy over time. The first two vaccines to be approved in the US, BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) both use an mRNA encoding the SARS-CoV-2 spike protein. A new study out of the U.K., which was conducted by a team at King’s College London and the Francis Crick Institute, found that delays in administering the second dose of more than 21 days leaves cancer patients vulnerable to COVID-19.. Covid-19 vaccination: What’s the evidence for extending the dosing interval? The results showed the single dose efficacy of AstraZeneca’s vaccine to be 76% after 21 days and showed negligible immune decay over three months. Spain's Health Ministry is considering delaying second doses of COVID-19 vaccines for under 80 year olds to maximise the number of people who have received at … 2021-02-03. Many people are skeptical of vaccines, fearing that the speed of development has necessitated cutting corners and that political pressure has influenced vaccine recommendations. The delayed second dose strategy was optimal for vaccine efficacies at or above 80% and vaccination rates at or below 0.3% of the population per day, under both sterilizing and non-sterilizing vaccine assumptions, resulting in absolute cumulative mortality reductions between 26 and 47 per 100 000. Delayed Second Dose vs. Standard Regimen for Covid-19 Vaccine This interactive feature about administration of the second dose of Covid-19 vaccine … A delayed second dose strategy either in people below 65 years old or the entire population did not show a cumulative mortality benefit compared with an on-schedule two dose regimen when the vaccination rate was 1% of the population or above. Spain mulls delaying second dose of Moderna and Pfizer shots, El Mundo reports . This additional vaccination strategy proposed using a delayed second dose strategy in people under 65 years old, but not before fully vaccinating those 65 and above. The Guardian. Initially, the scientists had developed the vaccines (Moderna, Pfizer-BioNTech, Oxford-AstraZeneca) in such a way that the second shot was advised to be administered within three to four weeks of the first dose. While the U.K. is recommending dose stretching as a deliberate strategy to get more first shots in more arms, the CDC is suggesting it as an option to make scheduling second shots less onerous. Results are shown for a vaccination rate of 0.3% of the population per day. The cumulative number of infections per 100 000 for standard versus delayed second dose was 69 577 versus 64 220, 69 350 versus 64 859, and 69 670 versus 65 891 for 90%, 80%, and 70% first dose efficacy, respectively. Delaying the second dose of the Moderna vaccine by 12–15 weeks could achieve the largest reduction of hospitalizations and deaths, according to the researchers’ model. Denmark authorized a six-week delay. Locations, December 2020-March 2021, The Effect of Age on Mortality in Patients With COVID-19: A Meta-Analysis With 611,583 Subjects, Modeling the effect of exposure notification and non-pharmaceutical interventions on COVID-19 transmission in Washington state, “Knocking on Doors that Don’t Open”: experiences of caregivers of children living with disabilities in Iquitos and Lima, Peru, Antibody Persistence through 6 Months after the Second Dose of mRNA-1273 Vaccine for Covid-19, Quantifying SARS-CoV-2 transmission suggests epidemic control with digital contact tracing, Alternative Dose Allocation Strategies to Increase Benefits From Constrained COVID-19 Vaccine Supply, Immunological memory to SARS-CoV-2 assessed for up to 8 months after infection, Phase I/II study of COVID-19 RNA vaccine BNT162b1 in adults, An mRNA Vaccine against SARS-CoV-2 - Preliminary Report, What we know about covid-19 reinfection so far. preprint. 9. 2021. In some cases, foreign countries, including Canada and Britain, are delaying the second dose of the Pfizer vaccine by months in favor of delivering as many first doses as possible. https://www.wesh.com/article/delaying-coronavirus-countries/35134442 Delaying the second dose of the Pfizer–BioNTech COVID-19 vaccine by 12 weeks after the first dose significantly boosts antibody responses in elderly people, according to a new U.K. study. Center for Disease Control and Prevention. Figure 4 explores the effect on cumulative mortality of an additional vaccination strategy that prioritizes second doses for people older than 65 years, across three different vaccination rates. Baden LR, El Sahly HM, Essink B, et al. With the continued large death toll from covid-19 and reports of mutant strains, each country is facing increasing urgency to vaccinate its population rapidly.23 The multiple vaccines in phase III trials offer promise for increasing availability and therefore vaccination rates, but BNT162b2 and mRNA-1273 still account for a large portion of the world’s covid-19 vaccine supply.1324 The strategy of delaying the second dose has been an active discussion given its ability to rapidly increase covid-19 immunity in the population by increasing single dose vaccination rates, but empiric research to understand its implications was lacking. 5. 2021. Covid-19 vaccines made by Moderna Inc., Pfizer Inc. - BioNTech SE, and AstraZeneca Plc are administered in two doses. To simulate a natural pattern of infection at the point vaccinations begin, we started our simulation with 10 agents infected and ran the simulation for 20 days before starting vaccinations, which corresponds to a cumulative infection rate of 1%, similar to the one in the US, UK, and most of Europe when vaccinations were started. UK science advisers: publish evidence behind COVID vaccine changes. The total number of deaths was lower for higher vaccination rates, as expected. This was estimated in the small subset of participants who did not receive the second dose during the trial.2327 As these were not defined study sub-groups, the advantages of randomization in preventing bias cannot be assumed to hold true, and unknown bias in these individuals is likely. By the day of the injection of the second dose, the efficacy of the first dose was somewhere in the range of 80 to 90%.1,2, Why consider delaying the second vaccine dose? Polack FP, Thomas SJ, Kitchin N, et al. The covid-19 pandemic continues to take thousands of lives daily worldwide. Results Over all simulation replications, the median cumulative mortality per 100 000 for standard dosing versus delayed second dose was 226 v 179, 233 v 207, and 235 v 236 for 90%, 80%, and 70% first dose efficacy, respectively. We used a broad range of vaccination rates because the vaccination rate in the US is in the range of 0.5-1% per day as of April 2021 but is much less than 0.5% per day for most other countries in the world.67. 2021. For a vaccination rates of 0.3% or lower, the delayed second dose strategy results in a lower cumulative mortality. Total mortality per 100 000 for standard versus delayed second dose was 226 versus 179, 233 versus 207, and 235 versus 236 for 90%, 80%, and 70% first dose efficacy, respectively. It is possible that some people will be confused by a change in the vaccine schedule, and the confusion may lead them to eschew vaccination altogether or believe that they need only a single dose. Our second analysis examined the effect of varying vaccination rates on total deaths by using the same two dosing regimens as our first analysis and a fixed single dose efficacy estimate of 80%, which we considered relatively conservative given our point estimate of 87%. For example, receiving a vaccination dose may change individuals’ behavior, affecting their risk of infection. Rasmussen A, Schwartz I. AIMIM chief Asaduddin Owaisi slammed Centre over shortage of Covid-19 vaccine doses. Disclosure forms provided by the author are available with the full text of this article at NEJM.org. Or do we use that same capacity to take a similar number of people from an unprotected state to one in which they are 80 to 90% protected? B.C. This suggests a vaccine efficacy from a single dose of 87%. Some European countries opted for delaying a second dose to get as many people as possible at least vaccinated with the first dose. The total cumulative mortality on day 180 is lower for the delayed second dose scenario under the assumption that the first dose effectiveness is ≥80%. Our findings also suggest that changes in cumulative mortality are larger than the corresponding decrease in the number of infections. Therefore, we believe this is a reasonable assumption, but it is one that decision makers should consider as more data become available. Germany was weighing on Monday whether to allow a delay in administering a second dose of the COVID-19 vaccine from BioNTech and Pfizer to make scarce supplies go … To account for immune decay, we analyzed existing and growing literature on the BNT162b2 and mRNA-1273 vaccines. Nature 2021;589:169-170. Conclusions A delayed second dose vaccination strategy, at least for people aged under 65, could result in reduced cumulative mortality under certain conditions. A study published in BMJ modelled impact of … Thirdly, several assumptions about the infectious spread (for example, the rate of contact between individuals in work, family, and random environments or the likelihood of infection during a random contact) were incorporated into the model, which seemed to match observations at the time the model was run, but these assumptions may not hold in all environments or if circumstances change. Thus, the number of cumulative infections was similar between the two strategies in these three scenarios studied. (Reuters) - The second dose of Pfizer Inc's COVID-19 vaccine could be delayed in order to cover all priority groups as the first one is highly protective, two Canada-based researchers said in a letter published in the New England Journal of Medicine. If these breakthrough cases appear to occur more frequently before the second, delayed dose, confidence will be further compromised, ultimately delaying the end of the pandemic and social and economic recovery. However, the immunogenicity of BNT162b2 and mRNA-1273 for a single dose was comparable to that of the plasma of people with previous covid-19 infection.3031 The reported re-infection rates of SARS-CoV-2 remain low within six months, and a lack of immune decay in this timeframe is also apparent.2932 In our study, we assumed no clinically relevant immune decay within 180 days for either the single or double dose of BNT162b2 and mRNA-1273 vaccines. Reuters. We display our results by using time series line plots over our 180 day modeling period, with a central line corresponding to the median value of our 10 runs for a given day and a shaded band corresponding to the 25-75% centile of values for a given day across all runs. If you are unable to import citations, please contact Concise summaries and expert physician commentary that busy clinicians need to enhance patient care. We do not capture any email address. Stay connected to what's important in medical research and clinical practice, Subscribe to the most trusted and influential source ofmedical knowledge, A Task Force on Administration of Covid-19 Vaccine. We also did a sensitivity analysis to consider the possibility that the vaccine prevents only symptomatic disease and not asymptomatic infection and spread. The global public health response to the covid-19 pandemic has resulted in the massive investment of resources into the production of an effective vaccine.1 This unparalleled approach has led to the development of multiple effective vaccines in record time. As cases spike, Europe mulls delaying 2nd coronavirus vaccine shot. A modeling study has advised delaying the second dose of coronavirus vaccine to save more lives, similar to the UK’s plan. You've already voted In terms of risk, Goel says there are risks all throughout the process. Delaying second dose of AstraZeneca by up to 12 weeks could increase immunity: study Devika Desai. With cases of COVID rising it is more important than ever to make sure people get the second does of the COVID vaccine. Holder J. Tracking coronavirus vaccinations around the world. Firstly, we used a range of estimates for single dose vaccine efficacy based on the CDC’s estimates and our own analysis, but the true efficacy may fall outside of those ranges. Total estimated mortality per 100 000 for delayed versus standard second dose was 402 versus 442, 204 versus 241, and 85 versus 50 for vaccination rates of 0.1%, 0.3%, and 1%, respectively. Vaccinating as many people as possible with initial doses before moving on to second doses is intended as the fastest means of inducing a good level of protection within the population. U.S. science agencies (the National Institutes of Health, the FDA, and the CDC) and vaccine developers alike are committed to making Covid-19 vaccine recommendations that are guided by science. Results are shown for a vaccination rate of 0.3% of the population per day. AJR, TCK, SRB, and EG drafted the manuscript, and KP, YD, JOH, WW, and MO revised it critically. Importance of 2nd dose. Catalonia will propose delaying the second dose of the Pfizer vaccine in ... Health Council meeting scheduled for Wednesday afternoon and urge Spain to follow the example of other European countries including France and Italy. 13. It is likely that supply constraints will ease within a month or two, as manufacturing becomes more efficient, and other vaccines will probably become available. 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